Drafting instrument



Feb. 27, 1951 L. P. FROST DRAFTING INSTRUMENT 2 Sheets-Sheet 1 Filed Aug. 20, 1946 L. P. FROST DRAFTING INSTRUMENT 2 sheets-Sheet 2 Feb. 27, 1951 Filed Aug. 20, 1946 Patented F eb. 27, 1951 UNITED STATES PATENT OFFICE DRAFTING INSTRUMENT Lester P. Frost, Placerville, Calif.

Application August 20, 1946, Serial No. 691,723

2 Claims.

This invention relates to a drafting instrument, and more particularly to an instrument adapted to be utilized with a scribing or writing instrument for drawing straight or curved lines.

A primary object of this invention is the provision of a device adapted to facilitate the drawing of straight lines of any length, and further, to facilitate the drawing of a plurality of parallel straight lines, or lines at an angle to a given base line.

An additional object of the invention is the provision of an instrument adapted to facilitate the drawing of arcs of any radii in an accurate and expeditious manner.

Still another object of the invention is the provision of such a device which may be readily adapted to a variety of drafting purposes, which is sturdy and durable in construction, reliable and eificient in operation, and relatively simple and inexpensive to manufacture and utilize.

Still other objects reside in the combinations of elements, arrangements of parts, and features of construction, all as will be more fully pointed out hereinafter, and disclosed in the accompanying drawings, wherein there are shown preferred embodiments of this inventive concept.

In the drawings:

Figure 1 is a side view, partially in elevation and partially in section, showing one form of device embodying features of the instant inventive concept.

Figure 2 is a rear View partially in elevation and partially in section of the device shown in Figure 1.

Figure 3 is a top plan view of the device.

Figure 4 is a reduced side elevational view of the device shown in association with a drawing pencil in one position of adjustment.

Figure 5 is a view similar to Figure 4, but showing a different position of adjustment.

Figure 6 is a side view partially in elevation and partially in section showing a modified form of construction.

Figure 7 is a bottom plan view of the device of Figure 6.

Figure 8 is a sectional view taken substantially along the line 8-8 of Figure '7, as viewed in the direction indicated by the arrows.

Figure 9 is an enlarged elevational view of a constructional detail.

Figure 10 is an enlarged sectional view taken through one of the supporting wheels of the de- Vice.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Having reference now to the modification disclosed in Figures 1 to 5, inclusive, there is generally indicated at ill a base member havinga recess or aperture l l therein which may be called a hollow base member. An upwardly extending arcuate flange 12 supports an angularly disposed cylindrical member 13 provided with a bore I 4 inclined downwardly toward the front of the base ID.

The bore I4 is adapted for the accommodation of a pencil I5, as best shown in Figures 4 and 5, or other desired implement which may take the form of a pen, a brush, a scribe, or the like, which instrument is adapted to be held in position within the bore, as by means of a set screw it, or any other suitable retaining means. An index plate I! is adapted to be positioned about the lower extremity of the base Ill and includes parallel straight sides [8 provided with suitable indicia indicative of angles, as well as a straight front side 19 provided with a depression 20 into which the point of a pencil [5 or the like is adapted to fit in such manner that the point is in perfect alignment with the indicia zero corresponding to the edge [9. The edges of the plate are extended, as at 2|, to provide for such zero indicia.

'Positioned within the recess H in the base ii! and on opposite sides thereof are spaced pairs of aligned depending lugs 25, each pair supporting an axle 26 upon which is mounted a wheel 21. The lugs 25 are positioned substantially adjacent the forward end of the base in. Rearwardly of the lugs 25 within the recess II and on opposite sides thereof are depending lugs 30 which support an axle 3| extending transversely across the recess substantially at right angles to the axle 2E.

The axle 3| supports adjacent the opposite extremities thereof wheels 32 of slightly lesser diameter than the wheels 2?. It will thus be seen that a line generated by the rotation of a wheel 32 will be at exactly right angles to that generated by the rotation of a wheel 21, and vice As best shown in Figure 10, both the wheels 21' and 32 are provided about their peripheries with tires 33 of suitable non-slipping material, such as rubber or the like.

From the foregoing the operation of the device should now be understandable. A pencil or other instrument is first adjusted in such manner that the tip extends into the recess 20 in the forward edge IQ of the index plate, and the body of the instrument is then grasped in. the same manner as a pencil, the fingers embracing the upwardly extending member [2. The instrument is then placed down on the material to be marked 50 that all the wheels 2'! and 32 rest on the paper, in which position movement of the device is difficult. If it is desired to draw a straight line, the body is tipped forwardly, as shown in Figure 4, until the pencil point contacts the paper, thus raising the wheels 32 with the device resting on the wheels 21, thus leaving the instrument free to travel in a transverse direction. After the line is drawn, if it is desired to draw a parallel line, the body may be tipped back until it rests on the Wheels 32 and the instrumentmoved a desired distance from the base line. When this position is reached, the body may be then tipped forward ofi the wheels 32 and a second line drawn parallel to the first.

In drawing a right angle, the instrument may be lifted free of the paper and placed down so that one of the sides N3 of theindex"-p1ate- I1 aligned with the base line, and a line perpendicular to the base line drawn in the manner hitherto described. Any angled line tothe base line may be drawn by'placing the in's'trument'down so that theappropriate-angledindicia of thedndxplate overlies the base line, whereupon" an angleiline' may be drawn in the manner previously" described. a

'A' modified form of'constructibn, which may be not only utilizedin the manner previously de scribed, but alsofor drawing curves of relatively. large radii is disclosed in Figures 6to 8, inclusive. This modification comprises a base Hi substantially identical'in configuration to base Hi having an interior recess H which may. be called a hollow base member, a flange l2, a tubular portion lt, includinga'n interior channel; and a set screw 16 for holdinga pencil'o'r similar instrument in the'bore.

Although not essential'to the use of this device, an index plate conforming in configuration to index plate i'l,.may. be'u'tiliz'ed iftdesired.

Pivotally mounted, as on. pivots M on opposite sides of the recess H adjacent the frontend thereof are a pair of brackets $2, each of which carries an axle 43 upon which is rotatably. mount-'- ed a wheel M corresponding in general configuration. and size to the previouslydescribed wheel 21'',

and'provided with tires o3 similar in configuration' thereto. Fixedly secured to each of'the brackets" 82" adjacent the pivot point thereof is an arm 45' whichv extends rearwardly and inwardly, the extremities of the" two. arms: being,

set it in orderto permit'the overlying. of the extremities above mentioned The extremity" of each arm as is provided with an elongated slot l'l and a pin 48' carried by a semi-cylindrical member 49 extending longitudinally of the base member Hi is adapted to extend into both of the slots? One end of the semi-cylindrical member ieextends into a corresponding aperture to in' 'a boss 51 extendinginwardly from theiront wall of the body i i. The opposite end of the guidemember it) comprises an integral portion of a cylindricalthreaded member52 which terminatei's inan enlargedfcylindric'alstub end fid provided with grad-- uations' Q thereon. A turning nutorirotatable element, comprised of a finger-engaging portion" 55; a flange 5t, and an annulusil surrouhds-2the portions 52 and 53, the annulusblbeing provided rotation of the turning nut 55 causes linear movement, through the threaded portion 52, of the semi-cylindrical member 49, and hence the pin 48. Movement of the pin. in turn moves the arms 45 to cause rotative movement: of the brackets 42 about their associated pivots 4B. Obviously, the degree of rotative movement may be designated by the indicia 54, and, since the wheels obviously are turned in opposite directions by such movement, the result defines an arc, the radius of which may be readily varied by appropriate adjustrnentof the nut 55.

Therecess II also carries a pair of depending brackets 60 which carry an axle Bl on the extremities of. which are supported wheelsBZ, the wheels 82 beingpositioned at substantially right angles to the position .of the wheelsf llfwhen the latter" are. in aligned relation; The function of the wheels'fiz. is obviously identical'ito that Ofjthe previously discussed wheels .32'.

In the modification above. just described," it will be understood. that with the wheels. 5421* in. aligned relationship; the device may be utilized ir'ia manner identicalt'o thatdescrib'ed incon' I or other" surface.

While in the foregoing a" pencil hasb'een de*' scribed" as particularly" applicable for use" with the" device, a specialtype' pen, as" disclosedin' Figural), may be also utilized for" inking 'if'ide sired. Thepen comprisesa straight point .101

" and a" bow' point"?! of conventional design, as

well as the customary'adjusting nut 12'. To the outer side of the straight point 10, a cylindrical shank 13' may be affixedset at" an anglecorre sponding. to the angle 'of the bore 14; in" such manner that the point"is"substantially perpendicular to the paper. Obviously, any other de' siredinstrumentmaybe utilized if desired? From the foregoing it' will now be seen" that there isherein provided an improved. drafting" instrument which accomplishes *allfthe objects of this inventiony'an'd others, including many. advantages of great practical utility and commer cial importance? As "many embodimentsmay be madeflo'ffthis inventive concept, and" as'many modifications may be madein V the embodiment 'hereinbef ore shownand de scribed, it' is to be understood that all matter herein'is to be interpretedmerelyas illustrative-*and not ina limiting sense.

l. adrafti-g instrument; hollow base member, a pair of horizontally" disposed arms converging toward-each other at one end-and positioned within said base-member, a horizontally disposed guide memberei'rtendihg longitudi' nally of a said base member positioned below 'and spaced 'fro'rnsaid arms and'a'mounted on said base member for linear movement, one end of said guide member: projecting beyond and: terminating at a' point exteriorly of said base member; a cylindrical stub provided with graduations thereon fixedly mounted on the projecti'ng end' of said guidemember, each' of said arms adjacen the converging end being 'provided with Ion i'-- nally- 'extendmg slot, a' vertically disposed pin-on said guide member and slidably engaging the slots in the converging ends of said arms, a wheel mounted for rotation about a horizontal axis positioned generally longitudinally of said base member adjacent to and below each of the other ends of said arms and operatively connected to the other end of said arm for movement about a vertical axis, a transversely disposed rotatable axle positioned within said base member below and spaced from said guide member and dependingly supported from said base member, a wheel positioned adjacent each end of said axle and fixedly secured thereto, said guide member being provided with a threaded portion extending inwardly from said stub and terminating at a point adjacent to and spaced from said pin, and a rotatable turning nut in threaded engagement with the threaded portion of said guide member for eifecting the linear movement of the latter.

2. In a drafting instrument, a hollow base member, a pair of horizontally disposed arms converging toward each other at one end and positioned within said base member. a horizontally disposed guide member extending longitudinally of said base member positioned below and spaced from said arms and mounted on said base member for linear movement, one end of said guide member projecting beyond and terminating at a point exteriorly of said base member, a cylindrical stub provided with graduations thereon fixedly mounted on the projecting end of said guide member, means slidably connecting each of the converging ends 01, said arms to said guide member, a wheel mounted for rotation about a horizontal axis positioned generally longitudinally of said base member adjacent to and below each of the other ends of said arms and operatively connected to the other end of said arm for movement about a vertical axis, a transversely disposed rotatable axle positioned within said base member below and spaced from said guide member and dependingly supported from said base member, a wheel positioned adjacent each end of said axle and fixedly secured thereto, and a rotatable element operatively connected to the portion of said guide member inwardly of said stub for efiecting the linear movement of said guide member.

LESTER P. FROST.

REFERENCES CITED The following references are of record in the.

file of this patent:

UNITED STATES PATENTS 

